Ubuntu Manpage: pmlogcheck - checks for invalid data in a PCP archive

NAME

       pmlogcheck - checks for invalid data in a PCP archive

SYNOPSIS

       pmlogcheck [-lmvwz?]  [-n pmnsfile] [-S start] [-T finish] [-Z timezone] archive

DESCRIPTION

       pmlogcheck prints information about the nature of any invalid data which it detects in the files of a PCP
       archive.

       The archive has the base name archive and must have been previously created using pmlogger(1).

OPTIONS

The available command line options are:

-l, --label
Print the archive label, showing the log format version, the time and date for the start and
(current) end of the archive, and the host from which the performance metrics values were collected.

-m, --metadataonly
Skip Pass 3 (see below) and only check the archive meta data. This can run substantially faster in
cases where the volume data doesn't need to be checked, especially on archives with compressed data
volume(s).

-n pmnsfile, --namespace=pmnsfile
Load an alternative Performance Metrics Name Space (PMNS(5)) from the file pmnsfile.

-S starttime, --start=starttime
Specify the starttime of time window over which metrics should be checked in Pass 3 (see below).
Refer to PCPIntro(1) for a complete description of the syntax for starttime.

-T endtime, --finish=endtime
Specify the endtime of time window over which metrics should be checked in Pass 3 (see below).
Refer to PCPIntro(1) for a complete description of the syntax for endtime.

-v, --verbose
Enable verbose mode.

-z, --hostzone
Use the local timezone of the host that is the source of the performance metrics archive. The
default is to use the timezone of the local host.

-Z timezone, --timezone=timezone
Use timezone for the date and time. Timezone is in the format of the environment variable TZ as
described in environ(7). The default is to use the timezone of the local host.

-?, --help
Display usage message and exit.

OPERATION

The checking proceeds in a number of passes, each designed to validate progressively more complex
semantic relationships between the information in a PCP archive.

Pass 0
Each physical file of the PCP archive is processed to ensure the label records are valid and consistent,
and that each file contains an integral number of physical records with correct header and trailer
fields.

Any errors at this stage are usually fatal. The PCP archive is probably damaged beyond repair, and no
more passes of pmlogcheck are attempted.

Pass 1
Validates the integrity of the temporal index, usually archive.index.

As the temporal index is (strictly speaking) optional, errors at this stage are handled by marking the
index as bad and ignoring it for the remainder of the pmlogcheck passes.

Permanent repair can be achieved by removing the temporal index file and then making a copy of the PCP
archive using pmlogrewrite(1) or pmlogextract(1). This will create a new temporal index for the copied
archive as a side-effect.

Pass 2
Validates the integrity of the metadata file, usually archive.meta.

Pass 3
Validates the integrity of each of the log volumes of the PCP archive, usually archive.0, archive.1, etc.

There is some basic integrity checks to ensure the encoding of values for each metric remains consistent
and the values are well formed across all the observations in the archive.

Also the timestamps for the observations are expected to be monotonically increasing as the archive is
tranversed.

Additional attention is given to counter metrics (type from pmLookupDesc(3) is PM_SEM_COUNTER) which are
expected to have monotonically increasing values. If the values are not monotonic increasing this may
suggest a counter wrap has happened or there has been some interruption or reset to the underlying source
of the performance data that is no captured in the archive.

For each counter metric which has been detected as having wrapped at some point in the archive,
pmlogcheck produces output describing the metric name (with instance identifiers where appropriate), the
internal storage type for the metric, the value of the metric before the counter wrap (with its
associated timestamp), and the value of the metric after the wrap (also with a timestamp).

The -w option may be used to suppress reporting of counter wraps.

pmlogcheck produces two different timestamp formats, depending on the interval over which it is run. For
an interval greater than 24 hours, the date is displayed in addition to the time at which the counter
wrap occurred. If the extent of the data being checked is less than 24 hours, a more precise format is
used (time is displayed with millisecond precision, but without the date).

DIAGNOSTICS

       All are generated on standard error and are intended to be self- explanatory.

FILES

       $PCP_VAR_DIR/pmns/*
            default PMNS specification files

       $PCP_LOG_DIR/pmlogger/<hostname>
            default directory for PCP archives containing performance data collected from the host hostname.

PCP ENVIRONMENT

       Environment  variables with the prefix PCP_ are used to parameterize the file and directory names used by
       PCP.  On each installation, the file /etc/pcp.conf contains the local values for  these  variables.   The
       $PCP_CONF variable may be used to specify an alternative configuration file, as described in pcp.conf(5).